The advent of stable, silicone rubbers started in the U.S. during the 1970's, but gained strength on new polydiorganosiloxane powered rubbers during the 1990's and this has led to new plastics modified with the modern silicone rubbers that have found use in such things as component parts for aircraft and trains, cookware, automobile components, machine parts, cabinetry and casing for electronic and computer systems, designed office and home furniture, and the like.
The provision of modern silicone rubbers came primarily from the inventors of the inventions found in U.S. Pat. No. 5,153,238, that issued on Oct. 6, 1992 to Bilgrien, et al; U.S. Pat. No. 3,824,208 that issued on Jul. 16, 1974 to Link et al, and U.S. Pat. No. 5,391,594 that issued on Feb. 21, 1995 to Romenesko, et al, in which free-flowing silicone polymer powders are taught. Said powders have an average particle size of 1 to 1000 microns and are prepared by mixing a polydiorganosiloxane with reinforcing silica filler.
It is taught by Romenesko in the '594 patent that when these powdered polymers are employed at a concentration of about 0.5 to 25 parts by weight of powder per 100 parts by weight of resin, significant improvement in the burn character of the modified resin is obtained such that the rate of heat release, generation of smoke and evolution of toxic carbon monoxide gas is significantly reduced relative to the unmodified resin.
For example, modification of thermoplastic resins has been taught in Romenesko in U.S. Pat. No. 5,288,674 and U.S. Pat. No. 5,508,323 that issued on Apr. 16, 1996, namely, polystyrene, high impact polystyrene, propylene, polycarbonate, polysulfone, poly(phenylene sulfide), acrylonitrile-butadiene-styrene copolymer, nylon, acetal, polyethylene, poly(ethylene terephthalate), poly(butylene terephthalate), acrylate, fluoroplastics, polyesters, phenolics, epoxies, urethanes, polyimides, melamine formaldehyde and urea.
Romenesko et al, in U.S. Pat. No. 5,916,952 discloses the modification of Poly(phenylene ether) resin using powered silicone polymers. Brewer et al, in U.S. Pat. No. 6,362,288 that issued Mar. 26, 2002 discloses the silicone modification of compatibilized polyamide resins. Chorvath et al, in U.S. Pat. No. 6,417,293 that issued Jul. 9, 2002 discloses the silicone modification of polyester resins.
In addition, Chorvath et al disclose thermoplastic silicone modified elastomers (polyamide or polyester resins) using radical cure techniques in U.S. Pat. No. 6,465,552, that issued Oct. 15, 2002 and Gross, et al in U.S. Pat. No. 5,569,958 that issued May 27, 2003 disclosed thermoplastic silicone elastomers from compatibilized polyester resins.
Further, Brewer, et al in U.S. Pat. No. 6,649,704 that issued on Nov. 18, 2003 disclose thermoplastic silicone elastomers from compatibilized polyamide resins and still further, Gornowicz et al, in U.S. Pat. No. 6,759,487 that issued on Jul. 6, 2004 disclose thermoplastic polyurethane silicone elastomers.
These patents teach modification of certain polymers that have tg's below about 90° C. and processing temperatures of less than 200° C., as these are the polymers that have fairly low complexity of handling. Polymers having tg's above about 95° C. along with melt processing temperatures at 250° C. or above have not been taught in the prior art nor have the benefits of such compositions been disclosed in the prior art.